Integrated circuits used for computing, communications, and other information services require electrical power to operate and generate heat as a bi-product of operations. As the density of the integrated circuit has increased according to More's law and as the speed of operation of computing devices has increased, both the power consumed by devices and the heat produced by devices have been increasing.
The increased power consumption of devices taxes the ability of the electronic system of which a device is a component in several ways. First and most obviously, the increased power demand requires a larger power source. In the case of stationary systems, this is not a huge impediment. In portable electronic applications, this increased power demanded from battery systems results in increased weight and/or shorter mission duration for the device. In addition, as system density continues to increase, the overhead associated with the physical distribution of power from a single central source becomes problematic.
The increased heat production of electronic devices requires the installation of ancillary systems on the electronic device itself. Usually the integration of further ancillary systems occurs within the overall packaging of the electronic system. Specifically, heat sinks are required to be attached to electronic chip packages to facilitate cooling. In some cases, the active movement of a coolant, like air, is required by some mechanical means. Once the chip level heat problem is addressed, further systems may be required to provide system level thermal management.
Other electrical devices commonly found in portable electronics also require cooling and are configured with heat sinks.
A need exists within electrical and electronic systems to provide ever increasing levels of power and also to provide ever increasing levels of thermal management, specifically cooling.
A fuel cell is a device that converts chemical energy directly into electrical power through a continuously replenished chemical reaction. Fuel cells are being proposed as an alternative power sources to primary or secondary batteries in portable electronics applications due to the improved performance characteristics of fuel cells in comparison to batteries. Fuel cells are advantageous because of improved energy density and extremely fast recharging (refueling). However, fuel cells proposed for use in portable electronics applications require air breathing cathodes to be continuously fed with oxidant. This requirement can increase system size and complexity. Also, fuel storage and processing options for such fuel cells are limited due to the requirement for consistently low temperature operation. While it is possible to develop very small high temperature devices, obtaining a source of process heat for fuel conditioning and operation requires ancillary systems for burning and consumes fuel. All of these factors detract from the utility of fuel cells as small portable electronic device power supplies.
A need exists within the development of fuel cell systems for electronic devices to integrate the system components with the application in order to minimize the overhead volume and weight associated with ancillary systems. Ideally, the fuel cell and ancillary systems could provide electrical power without consuming any extra volume within the enclosure of the electronics product and without the need for multiple discrete devices to effect the overall conversion from chemical energy stored in a fuel to electrical power for the electronic circuits.
A need exists for an integrated heat sink and fuel cell system in which the waste heat from an active electronic circuit and the volume in which the heat sink conventionally used to dissipate this heat into the environment are used to house a fuel cell system and to provide process heat for various endothermic processes employed in performing the chemical to electrical energy conversion. A need has existed for an invention to provide power to an electronic devise using a fuel stored in an external tank with no extra volume is required to house the fuel cell system. The present invention has been designed to meet these needs.